Oxadiazole ultraviolet stabilizers and their use in organic compositions

ABSTRACT

The invention relates to heterocyclic ester compounds which have been found to be extremely effective ultraviolet stabilizers. The invention also relates to ultraviolet degradable organic compositions containing an amount of a heterocyclic ester composition to prevent such degradation. These stabilizers are effective in the presence of other additives commonly employed in polymeric compositions including, for example, pigments, colorants, fillers, reinforcing agents and the like. These ultraviolet stabilizers may also be incorporated into the organic compositions such as polymers by adding to the polymer melt or dissolved in the polymer dope, coated on the exterior of the shaped or molded article, film or extruded fiber.

This is a division of Ser. No. 955,449, filed Oct. 27, 1978, now U.S.Pat. No. 4,236,013, issued Nov. 25, 1980 which is a division of Ser. No.797,667, filed Dec. 17, 1976, now U.S. Pat. No. 4,137,235, issued Jan.30, 1979 which is a continuation of Ser. No. 484,846, filed July 1,1974, now abandoned.

This invention relates to ultraviolet stabilizers and their use inorganic compositions. More particularly, the invention relates toheterocyclic ester compositions and the stabilization of organiccompositions against deterioration resulting from the exposure to lightwith such heterocyclic ester compositions.

The degradative effects of ultraviolet light on various organiccompositions is well known in the art. The photo-deterioration ordegradation is of particular concern with organic photo-degradablecompositions which are exposed to ultraviolet light, such as sunlight,for long periods of time. One group of such photo-degradable organiccompositions is polymeric compositions such as polyolefins, polyestersand the like. On exposure to sunlight for extended periods of time,these polymeric compositions degrade and their physical properties arereduced to render the polymeric composition less useful for mostapplications. Therefore, considerable effort has been directed toproviding a solution to the photo-degradation problem of polymericcompositions. As a result of this effort, there have been discoveredmany additives and stabilizers which improve the stability of polymericcompositions.

Moreover, various additives and stabilizers exhibit the power to absorbelectromagnetic radiation within the band of 2900 to 4000 A. and whenincorporated in various plastic materials such as transparent sheets,the resultant sheet acts as a filter for all of the radiation passingthrough and will transmit only such radiations as are not absorbed bythe sheet and/or the absorbing agent. It is thus possible to screen outundesirable radiations and utilize the resulting transparent sheet as afilter in many technical and commercial applications such as wrappingsfor food products and the like.

While there are many additives, stabilizers and mixtures thereof whichare known in the art to improve the ultraviolet light stability oforganic compositions, there is a need in the art for more efficient andeffective stabilizers to prevent the photo-degradation of organiccompositions susceptible to photo-degradation. Therefore, to provide amore effective and efficient ultraviolet stabilizer for organiccompositions susceptible to such degradation would be an advance in thestate of the art.

It is therefore an object of the present invention to providecompositions characterized by improved resistance to degradation anddeterioration by ultraviolet radiation.

It is still another object of the present invention to providecompositions containing heterocyclic ester compositions which areresistant to ultraviolet degradation.

It is a still further object of this invention to provide processes forimproving the resistance of organic materials to deterioration anddegradation by actinic radiation and especially ultraviolet radiation.

It is a still further object of this invention to provide compositionsand processes for improving the resistance of organic materials todeterioration and degradation by actinic radiations including shortwave-length visible radiations.

Further objects and advantages of the invention will be apparent tothose skilled in the art from the accompanying disclosure and claims.

In accordance with the present invention, organic compositions areprovided which are useful as ultraviolet stabilizers. These organiccompositions contain a heterocyclic group connected through a carboxylgroup to an aromatic ring which upon exposure to ultraviolet light mayundergo the "photo-Fries" rearrangement. The organic compositions of thepresent invention are aryl esters of heterocyclic aromatic acids havingthe following structure: ##STR1## wherein A is a heterocyclic memberselected from the group consisting of substituted and unsubstituted1,3,4-oxadiazole, 1,3,4-thiadiazole, 1,3,4-triazole, benzoxazole,benzothiazole, benzimidazole, thiazole, oxazole, imidazole, and indole,and the like.

Such suitable A components are, for example, members having theformulae: ##STR2## wherein

X and Y are a carbon atom or a nitrogen atom;

Z is an oxygen atom, a sulfur atom, a nitrogen atom, or a nitrogen atomcontaining a hydrogen atom or a substituted or unsubstituted lower alkylgroup having 1 to 12 carbon atoms;

R₁, R₂, R₃, R₄ and R₅ are hydrogen, lower alkyl, substituted loweralkyl, cycloalkyl, substituted cycloalkyl, aryl, substituted aryl, loweralkylaryl, aryl-substituted-aryl, chloro, bromo, alkoxy, alkylsulfonyl,substituted amino, cyano, nitrile, and the substituents R₂, R₃, R₄ andR₅, combined with the carbon atoms to which they are attached, arejoined alkylene groups completing a carbocyclic ring which ring can besubstituted with any of the substituents listed above for R₁ through R₅.

Suitable A groups having the formula ##STR3## are, for example,substituted and unsubstituted 2-oxadiazolyl, 2-thiazolyl, 2-triazolyl,2-oxazolyl, and 2-imidazolyl and the like.

Examples of suitable 2-oxadiazolyl moieties are those having theformula: ##STR4## such as 5-(4-chlorophenyl)-1,3,4-oxadiazol-2-yl,5-phenyl-1,3,4-oxadiazol-2-yl, 5-methylsulfonyl-1,3,4-oxadiazol-2-yl,5-(2,4-dichlorophenyl)-1,3,4-oxadiazol-2-yl,5-methyl-1,3,4-oxadiazol-2-yl, 5-(4-phenyl)phenyl-1,3,4-oxadiazol-2-yl,5-cyano-1,3,4-oxadiazol-2-yl, 5-(4-cyanophenyl)-1,3,4-oxadiazol-2-yl,and 5-(4-methoxyphenyl)-1,3,4-oxadiazol-2-yl, and the like.

Examples of suitable 2-thiadiazolyl moieties are those having theformula: ##STR5## such as 5-phenyl-1,3,4-thiadiazol-2-yl,5-(4-chlorophenyl)-1,3,4-thiadiazol-2-yl,5-methylsulfonyl-1,3,4-thiadiazol-2-yl, 5-ethoxy-1,3,4-thiadiazol-2-yl,5-phenyl-1,3,4-thiadiazol-2-yl,4-(4-phenyl)phenyl-1,3,4-thiadiazol-2-yl,4-cyclohexyl-1,3,4-thiadiazol-2-yl,5-(3-methoxyphenyl)-1,3,4-thiadiazol-2-yl, and5-cyano-1,3,4-thiadiazol-2-yl, and the like.

Examples of suitable 2-triazolyl moieties are those having the formula:##STR6## wherein Q is hydrogen or a substituted or unsubstituted loweralkyl group containing 1 to 12 carbon atoms, such as5-phenyl-1,3,4-triazol-2-yl, 5-(4-cyanophenyl)-1,3,4-triazol-2-yl,5-cyano-1,3,4-triazol-2-yl, 4-(4-methoxyphenyl)-1,3,4-triazol-2-yl,1-(n-butyl)-5-(2,4-dichlorophenyl)-1,3,4-triazol-2-yl,1,3,4-triazol-2-yl, 1H-5-phenyl-1,3,4-triazol-2-yl,1H-5-methylsulfonyl-1,3,4-triazol-2-yl,1-methyl-5-phenyl-1,3,4-triazol-2-yl, and the like.

Examples of suitable 2-oxazolyl moieties are those having the formula:##STR7## wherein J is the same as R₁, such as 5-phenyl-2-oxazolyl,4,5-diphenyl-2-oxazolyl, 4,5-dimethyl-2-oxazolyl,4-chloro-5-cyano-2-oxazolyl, 4-phenyl-5-cyano-2-oxazolyl,5-methylsulfonyl-2-oxazolyl, 5-cyclohexyl-2-oxazolyl,4,5-dichloro-2-oxazolyl, 5-ethoxy-2-oxazolyl, and the like.

Examples of suitable 2-thiazolyl moieties are those having the formula:##STR8## wherein J is the same as R₁, such as4-phenyl-5-chloro-2-thiazolyl, 4,5-dichloro-2-thiazolyl,4-chloro-5-cyano-2-thiazolyl, 4-ethoxy-5-phenyl-2-thiazolyl,4,5-dimethyl-2-thiazolyl, 4,5-dicyano-2-thiazolyl, 5-phenyl-2-thiazolyl,and the like.

Examples of suitable 2-imidazolyl moieties are those having the formula:##STR9## wherein J is the same and R₁ and Q is hydrogen or a substitutedor unsubstituted lower alkyl having 1 to 12 carbon atoms, such as1-methyl-4,5-diphenyl-2-imidazolyl, 4-chloro-5-cyano-2-imidazolyl,5-phenyl-2-imidazolyl, 1-ethyl-5-phenyl-2-imidazolyl,4,5-diphenyl-2-imidazolyl, 1-benzyl-4-phenyl-5-cyano-2-imidazolyl,1-methyl-4-cyano-2-imidazolyl, 4-methoxy-5-phenyl-2-imidazolyl,4,5-dichloro-1-benzyl-2-imidazolyl, and the like.

Suitable A groups having the formula ##STR10## are, for example,substituted and unsubstituted 2-benzoxazolyl, 2-benzothiazolyl,2-benzimidazolyl and 2-imidolyl.

Examples of suitable 2-benzoxazolyl moieties are those having theformula ##STR11## such as 5,6-dimethyl-2-benzoxazolyl, 2-benzoxazolyl,5-chloro-2-benzoxazolyl, 5,6-dichloro-2-benzoxazolyl,4,5-diethyl-2-benzoxazolyl, 5-cyano-2-benzoxazolyl,5-methoxy-6-methyl-2-benzoxazolyl, 4-chloro-5-phenyl-2-benzoxazolyl, andthe like.

Examples of suitable 2-benzothiazolyl moieties are those having theformula ##STR12## such as 2-benzothiazolyl,5,6-dimethyl-2-benzothiazolyl, 5,6-dichloro-2-benzothiazolyl,5-chloro-2-benzothiazolyl, 5-methoxy-2-benzothiazolyl,6-methylsulfonyl-2-benzothiazolyl, 6-cyano-2-benzothiazolyl,6-methylthio-2-benzothiazolyl, and 6-methyl-2-benzothiazolyl.

Examples of suitable 2-benzimidazolyl moieties are those having theformula ##STR13## wherein Q is hydrogen or a substituted orunsubstituted lower alkyl containing 1 to 12 carbon atoms, such as2-benzimidazolyl, 1-methyl-2-benzimidazolyl,1,5,6-trimethyl-2-benzimidazolyl, 6-cyano-1-ethyl-2-benzimidazolyl,6-chloro-2-benzimidazolyl, 5-methoxy-1-benzyl-2-benzimidazolyl,6-methylsulfonyl-2-benzimidazolyl, 4-methoxy-1-methyl-2-benzimidazolyl,and the like.

Examples of suitable indole moieties are those having the formula##STR14## wherein G is the same as R₁, and Q is hydrogen or asubstituted or unsubstituted lower alkyl containing 1 to 12 carbonatoms. Such suitable indole moieties are, for example,1-ethyl-3-cyano-2-indolyl, 5-chloro-2-indolyl, 1-methyl-2-indolyl,3-methyl-2-indolyl, 3-chloro-2-indolyl, 5-acetamido-2-indolyl,2-indolyl, 1-ethyl-2-indolyl, 3-cyano-2-indolyl, 5-methoxy-2-indolyl,1-methyl-2-indolyl, 3-methyl-5-phenyl-2-indolyl and3,5-dichloro-2-indolyl.

Suitable B groups having the formula ##STR15## are 2,4-dimethoxyphenyl,3-methoxyphenyl, 3-methylphenyl, 4-octylphenyl, 4-dodecylphenyl,3-octylphenyl, 2,4-dichlorophenyl, 4-methoxyphenyl,2,4-di-t-butylphenyl, 3-(2-ethylhexyloxy)phenyl, 3-dodecyloxyphenyl,4-cyanophenyl, 4-bromophenyl, 3-hydroxyphenyl and 3-cyclohexylphenyl.

"Lower alkyl" as used in this application means branched or unbranched,substituted or unsubstituted alkyl groups containing 1 to 12 carbonatoms. The substituents on the lower alkyl groups can be any of thoselisted hereinabove for R₁. "Alkyl" as used herein means branched orunbranched, substituted or unsubstituted alkyl groups containing 1 to 20carbon atoms which are substituted with the same substituents as R₁.Substituted aryl and cycloalkyl groups are also substituted by the samesubstituents as R₁. The "alk" of alkoxy and carboalkoxy means an alkylradical containing 1 to 20 carbon atoms.

The heterocyclic esters can be prepared by reacting the acid chloridewith a phenol. For example, one such group of organic compounds usefulas ultraviolet stabilizers is, for example, benzoxazole ester-basedcompositions having the formula ##STR16## These organic compounds can beprepared according to the following procedure: ##STR17## Substituents R₂through R₁₀ are defined hereinabove. It is necessary that at least oneof R₆ or R₁₀ be hydrogen so that, on exposure to ultraviolet light, thearyl ester of the heterocyclic aromatic acid is capable by the"photo-Fries" rearrangement of forming a phenol group in that positionformerly joined through an oxygen atom to the carbonyl linking group, asfor example ##STR18##

The acid chlorides (I) were prepared by reaction of the correspondingacid [See Zh. Obshch. Khim., 38, 100 1-5 (1968); Chem. Abstr. 69, 96568(1968)] with freshly distilled thionyl chloride [See J. Chem. Soc. 101,2476 (1912)]. The phenols were obtained from commercial sources, or wereprepared by standard methods; a critical requirement is that one of thepositions adjacent to the phenolic hydroxyl group be unsubstituted. Itis believed that the "photo-Fries" rearrangement can occur uponultraviolet exposure of the esters III and that these rearrangementproducts IV are effective stabilizers.

The heterocyclic ester compositions can be added to organic compositionswhich are susceptible to ultraviolet degradation. Such compositionsinclude, for example, polymeric compositions such as polyester fiber andmoldable compositions, such as poly(ethylene terephthalate),poly(tetramethylene terephthalate) and the like; unsaturated polyesters;polyolefins such as, for example, high, medium and low densitypolyethylene, polypropylene, polybutene and the like; polyamides such asnylon 6, nylon 66 and the like; polycarbonates; poly(vinyl chloride);cellulose esters; cellulose ethers; acrylic/butadiene/styrene plastic;acrylics such as polymethyl methacrylate; polystyrene; and gelatin. Suchcompositions also include natural and synthetic rubbers such aspolybutadiene, and unsaturated organic compositions such as oils and thelike, as well as compositions containing such organic compositions.

The heterocyclic ester compositions as effective ultraviolet stabilizersor screening agents are generally used in an amount of from 0.01 to 10%,by weight, based on the weight of the organic material to which they areadded. While a detectable amount of ultraviolet screening andstabilization may be obtained with amounts less than 0.01%, this amountof stabilization or screening would be of little practical utility in acommercial application. Moreover, while amounts greater than 10%, byweight, provide effective ultraviolet stability and screening, suchconcentrations are undesirable because of cost and the deleteriouseffect which such concentrations may have on the mechanical propertiesof the organic composition in which the stabilizer is incorporated.Preferably, the stabilizer is used in an amount of from about 0.1 toabout 5%, by weight. For example, an amount of 2%, by weight, of thestabilizer effectively stabilizes cellulose acetate butyrate plasticcompositions.

The ultraviolet stabilized organic compositions of the present inventionmay also contain other additives, pigments, colorants, stabilizers andthe like. For example, polymeric compositions, such as polyolefins, mayalso contain and generally do contain other additives such as white orcolored pigments or colorants, antioxidants, plasticizers, flow aids,processing aids, polymeric modifiers and the like.

These heterocyclic ester ultraviolet stabilizers may be incorporatedinto organic compositions by melt-blending or may be added onto thesurface of an organic plastic material prior to being molded into asuitable object, or added to the surface of the molded object. Thesematerials can also be added to coatings and the like which can beapplied to the surface of a molded object.

This invention will be further illustrated by the following examples,although it will be understood that these examples are included merelyfor purposes of illustration and are not intended to limit the scope ofthe invention.

EXAMPLE 1

4-(1,1,3,3-Tetramethylbutyl)phenyl4-chloro-5-phenyloxazole-2-carboxylate can be prepared by the followingprocedure:

To a solution of 4.0 g. (0.1 mole) of sodium hydroxide in 200 ml. ofwater was added 20.6 g. (0.1 mole) of4-(1,1,3,3-tetramethylbutyl)phenol. The mixture was stirred for 10minutes and 200 ml. of chloroform was added, followed by the dropwiseaddition of a solution of 24.2 g. (0.1 mole)4-chloro-5-phenyl-2-oxazolecarbonyl chloride in 500 ml. of chloroform.The mixture was stirred at reflux for 3 hours after the addition wascomplete. The reaction mixture was cooled to 30° C. and the chloroformlayer separated and washed with water. The solvent was removed bydistillation, the residue triturated with 100 ml. chilled isopropylalcohol, and the crude product collected by filtration. The tan solidwas recrystallized from toluene to give 26 g. of white solid.

Other oxazole esters can be prepared by substituting otheroxazolecarbonyl chlorides, such as 4,5-dimethyl-2-oxazolecarbonylchloride, 4-chloro-5-cyano-2-oxazolecarbonyl chloride,4,5-diphenyl-2-oxazolecarbonyl chloride,4-phenyl-5-cyano-2-oxazolecarbonyl chloride,5-methylsulfonyl-2-oxazolecarbonyl chloride,5-cyclohexyl-2-oxazolecarbonyl chloride, 4,5-dichloro-2-oxazolecarbonylchloride, 5-ethoxy-2-oxazolecarbonyl chloride,5,6-dimethyl-2-benzoxazolecarbonyl chloride, 2-benzoxazolecarbonylchloride, 5-chloro-2-benzoxazolecarbonyl chloride,5,6-dichloro-2-benzoxazolecarbonyl chloride,5,6-diethyl-2-benzoxazolecarbonyl chloride,5-cyano-2-benzoxazolecarbonyl chloride,5-methoxy-6-methyl-2-benzoxazolecarbonyl chloride, for4-chloro-5-phenyl-2-oxazolecarbonyl chloride.

Also, other oxazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methoxyphenol, 3-methylphenol,4-octylphenol, 4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol,3-bromophenol, 4-chlorophenol, 3-phenoxyphenol, 3-dodecyloxyphenol,3-n-butoxyphenol, 4-cyanophenol, 4-cyclohexylphenol, 4-phenylphenol,resorcinol, 2,4-dimethylphenol, 4-methoxyphenol, 2,4-di-t-butylphenol,for 4-(1,1,3,3-tetramethylbutyl)phenol.

EXAMPLE 2

3-Methylphenyl 4,5-diphenylthiazole-2-carboxylate can be similarlyprepared by the procedure of Example 1 as follows:

10.8 g. m-cresol (0.1 mole) was added to a solution of 4.0 g. (0.1 mole)sodium hydroxide in 200 ml. of water. A solution of 30 g. of4,5-diphenyl-2-thiazolecarbonyl chloride was added and refluxingcontinued for 3 hours. On workup, 31 g. of a white solid was obtained.

Other thiazole esters can be prepared by substituting otherthiazolecarbonyl chlorides, such as 4-phenyl-5-chloro-2-thiazolecarbonylchloride, 4,5-dichloro-2-thiazolecarbonyl chloride,4-chloro-5-cyano-2-thiazolecarbonyl chloride,4-ethoxy-5-phenyl-2-thiazolecarbonyl chloride,4,5-dimethyl-2-thiazolecarbonyl chloride, 4,5-dicyano-2-thiazolecarbonylchloride, 5-phenyl-2-thiazolecarbonyl chloride, 2-benzothiazolecarbonylchloride, 5,6-dimethyl-2-benzothiazolecarbonyl chloride,5,6-dichloro-2-benzothiazolecarbonyl chloride,5-chloro-2-benzothiazolecarbonyl chloride,5-methoxy-2-benzothiazolecarbonyl chloride,6-methylsulfonyl-2-benzothiazolecarbonyl chloride,6-cyano-2-benzothiazolecarbonyl chloride,6-methylthio-2-benzothiazolecarbonyl chloride and6-methyl-2-benzothiazolecarbonyl chloride for4,5-diphenylthiazole-2-carboxylic acid chloride.

Also, other thiazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methoxyphenol, 3-methylphenol,4-octylphenol, 4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol,3-bromophenol, 4-chlorophenol, 3-phenoxyphenol, 3-dodecyloxyphenol,3-n-butoxyphenol, 4-cyanophenol, 4-cyclohexylphenol, 4-phenylphenol,resorcinol, 2,4-dimethylphenol, 4-methoxyphenol, 2,4-di-t-butylphenol,for m-cresol.

EXAMPLE 3

4-Dodecyloxyphenyl 1-methyl-5-phenylimidazole-2-carboxylate cansimilarly be prepared by the procedure of Example 1 by reactingp-dodecyloxyphenol (27.8 g.) with 22 g.1-methyl-5-phenylimidazole-2-carbonyl chloride to provide 41 g. lighttan product.

Other imidazoles can be prepared by substituting5-phenylimidazole-2-carbonyl chloride,1-ethyl-5-phenylimidazole-2-carbonyl chloride,4,5-diphenylimidazole-2-carbonyl chloride,1-benzyl-4-phenyl-5-cyanoimidazole-2-carbonyl chloride,1-methyl-4-cyanoimidazole-2-carbonyl chloride,4-methoxy-5-phenylimidazole-2-carbonyl chloride,4,5-dichloro-1-benzylimidazole-2-carbonyl chloride,benzimidazole-2-carbonyl chloride, 1-methylbenzimidazole-2-carbonylchloride, 1,5,6-trimethylbenzimidazole-2-carbonyl chloride,6-cyano-1-ethylbenzimidazole-2-carbonyl chloride,6-chlorobenzimidazole-2-carbonyl chloride,5-methoxy-1-benzylbenzimidazole-2-carbonyl chloride,6-methylsulfonylbenzimidazole-2-carbonyl chloride,4-methoxy-1-methylbenzimidazole-2-carbonyl chloride, for1-methyl-5-phenylimidazole-2-carbonyl chloride.

Also, other imidazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methoxyphenol, 3-methylphenol,4-octylphenol, 4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol,4-methoxyphenol, 3-bromophenol, 4-chlorophenol, 3-phenoxyphenol,3-dodecyloxyphenol, 3-n-butoxyphenol, 4-cyanophenol, 4-cyclohexylphenol,4-phenylphenol, resorcinol, 2,4-dimethylphenol, 2,4-di-t-butylphenol,for p-dodecyloxyphenol.

EXAMPLE 4

3-Methoxyphenyl 5-phenyl-1,3,4-oxadiazole-2-carboxylate can be preparedby the procedure of Example 1 by reacting 3-methoxyphenol (12.4 g.) with21 g. 5-phenyl-1,3,4-oxadiazole-2-carbonyl chloride to provide 24 g.colorless product.

Other oxadiazole esters can be prepared by substituting5-methyl-1,3,4-oxadiazole-2-carbonyl chloride,5-(4-phenyl)phenyl-1,3,4-oxadiazole-2-carbonyl chloride,5-cyano-1,3,4-oxadiazole-2-carbonyl chloride,5-(4-cyanophenyl)-1,3,4-oxadiazole-2-carbonyl chloride, and5-(4-methoxyphenyl)-1,3,4-oxadiazole-2-carbonyl chloride,1,3,4-oxadiazole-2-carbonyl chloride,5-chloro-1,3,4-oxadiazole-2-carbonyl chloride,5-chloromethyl-1,3,4-oxadiazole-2-carbonyl chloride,5-dimethylamino-1,3,4-oxadiazole-2-carbonyl chloride for5-phenyl-1,3,4-oxadiazole-2-carbonyl chloride.

Also, other oxadiazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methylphenol, 4-octylphenol,4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol, 3-bromophenol,4-chlorophenol, 3-phenoxyphenol, 3-dodecyloxyphenol, 3-n-butoxyphenol,4-cyanophenol, 4-cyclohexylphenol, 4-phenylphenol, resorcinol,2,4-dimethylphenol, 4-methoxyphenol, 2,4di-t-butylphenol,4-methylphenol, 3-chlorophenol, 3,5-dimethyl-4-cyanophenol for3-methoxyphenol.

EXAMPLE 5

4-Chlorophenyl 5-cyano-1,3,4-thiadiazole-2-carboxylate can be preparedby reacting 4-chlorophenol (12.9 g.) with 17.4 g.5-cyano-1,3,4-thiadiazole-2-carbonyl chloride as in Example 1 to give 22g. light tan product.

Other thiadiazole esters can be prepared by substituting5-ethoxy-1,3,4-thiadiazole-2-carbonyl chloride,5-phenyl-1,3,4-thiadiazole-2-carbonyl chloride,5-(4-phenyl)phenyl-1,3,4-thiadiazole-2-carbonyl chloride,5-cyclohexyl-1,3,4-thiadiazole-2-carbonyl chloride, and5-(3-methoxyphenyl)-1,3,4-thiadiazole-2-carbonyl chloride for5-cyano-1,3,4-thiadiazole-2-carbonyl chloride.

Also, other thiadiazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methoxyphenol, 3-methylphenol,4-octylphenol, 4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol,3-bromophenol, 3-phenoxyphenol, 3-dodecyloxyphenol, 3-n-butoxyphenol,4-cyanophenol, 4-cyclohexylphenol, 4-phenylphenol, resorcinol,2,4-dimethylphenol, 4-methoxyphenol, 2,4-di-t-butylphenol, for4-chlorophenol.

EXAMPLE 6

3-Octyloxyphenyl 1,3,4-triazole-2-carboxylate can be prepared byreacting 3-octyloxyphenol (22.2 g.) with 13 g. 1,3,4-triazole-2-carbonylchloride as in Example 1 to yield 14 g. colorless product.

Other triazole esters can be prepared by substituting5-phenyl-1,3,4-triazole-2-carbonyl chloride,5-(4-cyanophenyl)-1,3,4-triazole-2-carbonyl chloride,5-cyano-1,3,4-triazole-2-carbonyl chloride,5-(4-methoxyphenyl)-1,3,4-triazole-2-carbonyl chloride, and1-(n-butyl)-5-(2,4-dichlorophenyl)-1,3,4-triazole-2-carbonyl chloridefor 1,3,4-triazole-2-carbonyl chloride.

Also, othe triazole esters can be prepared by substituting otherphenols, such as 2,4-dimethoxyphenol, 3-methoxyphenol, 3-methylphenol,4-octylphenol, 4-dodecylphenol, 3-octylphenol, 2,4-dichlorophenol,4-methoxyphenol, 3-bromophenol, 4-chlorophenol, 3-phenoxyphenol,3-dodecyloxyphenol, 3-n-butoxyphenol, 4-cyanophenol, 4-cyclohexylphenol,4-phenylphenol, resorcinol, 2,4-dimethylphenol, 2,4-di-t-butylphenol,for 3-octyloxyphenol.

EXAMPLE 7

3-Methoxyphenyl 1-methylindole-2-carboxylate can be prepared by theprocedure of Example 1 by reacting 3-methoxyphenol (12.4 g.) with 19 g.1-methylindole-2-carbonyl chloride to provide 22 g. light tan product.

Other indole esters can be prepared by substituting1-benzyl-3-chloroindole-2-carbonyl chloride, 3-cyanoindole-2-carbonylchloride, 1,3,5-trimethylindole-2-carbonyl chloride,1-ethyl-3-cyanoindole-2-carbonyl chloride,1-methyl-3-phenyl-5-chloroindole-2-carbonyl chloride for1-methylindole-2-carbonyl chloride.

EXAMPLE 8

The stabilizing effects of the ultraviolet stabilizers of the presentinvention in polyester plastic are shown in the following table:

    ______________________________________                                        Weathering Results for Stabilizers in                                         Poly(tetramethylene terephthalate) Plastic                                    Additive Compound                                                                           FWIS.sup.b                                                      (at 1%).sup.a 0          300     500                                          ______________________________________                                        Example 1     18         18      18                                           2             19         18      12                                           3             19         18      16                                           4             19         18      14                                           5             19         18      13                                           6             18         18      16                                           7             19         18      18                                           None          18         6       1                                            ______________________________________                                         .sup.a Incorporated into the polyester (1.50 I.V.) by dryblending the         powdered components, extrusion into 1/16" diameter rod and injection          molding into 1/16" thick flat bars.                                           .sup.b FlatwiseImpact-Strength (ft. lb./in..sup.2) after exposure to          mercury lamps for the hours indicated.                                   

These esters of heterocyclic aromatic acid compositions find particularutility as ultraviolet stabilizers in organic compositions requiringultraviolet stability. Such compositions include polymeric compositionssuch as, for example, polyester fiber and molding compositions;poly-α-olefins; polyamides; acrylics; cellulose esters and the like, aswell as molded or shaped articles, film and coatings formed from suchmaterials, and the like. Such compositions also include natural andsynthetic rubbers, such as natural rubber, as well as organic materialssuch as oils, fats, and unsaturated organic materials, and materialshaving such materials contained therein, such as paints, varnishes,cosmetics and the like.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

We claim:
 1. A composition of matter having the formula: ##STR19##wherein R₁ is hydrogen, chloro, bromo, lower alkyl containing 1 to 12carbon atoms, cyclohexyl, phenyl, lower alkyl phenyl, phenyl-substitutedphenyl, alkoxy containing an alkyl radical containing 1 to 20 carbonatoms, chloromethyl and dimethyl amino; at least one R₂ or R₆ ishydrogen and the other R₂, R₃, R₄, R₅ and R₆ are hydrogen, lower alkylhaving 1 to 12 carbon atoms, cyclohexyl, phenyl, lower alkyl phenyl,phenyl-substituted-phenyl, alkoxy containing an alkyl radical containing1 to 20 carbon atoms, dimethyl substituted amino, hydroxy, nitrile,chloro and bromo.
 2. A composition of matter according to claim 1 havingthe formula: ##STR20##
 3. A composition of matter according to claim 1having the formula: ##STR21##
 4. A composition of matter according toclaim 1 having the formula: ##STR22##
 5. A composition of matteraccording to claim 1 having the formula: ##STR23##
 6. A composition ofmatter according to claim 1 having the formula: ##STR24##
 7. Acomposition of matter according to claim 1 having the formula: ##STR25##8. A composition of matter according to claim 1 having the formula:##STR26##